If you create sales order without companies, for example in the case of sales to private individuals, the save process is very slow if there are many records in the database, because it is recalculated the association products-companies.
The problem is present in the function "recalculateAccToServices" and "recalculateAccToProducts".
To resolve this issue can be replaced, the line 160 and 192 of the file /modules/SalesOrder/SalesOrder.php the string